Markets offers so many Business Intelligence Platforms. In this way, bellow is detailed a product analysis, elaborated by one of the main technology observatory market analysis:Magic Quadrant for Business Intelligence Platforms
Source: Gartner (January 2011)At a high level, the Business Intelligence Aplication consists of:
An analytical database that store analytical information.ETL process that manage the analytical data, in order to provide information from different sources.Oracle BI that enables end-user access into the analytical data.
Below we identified costs involved. In concret, three year total cost of license and support by vendor and scenario:

Hope it helps.
Best Wishes.
Joan.